Tinggi kerucut 48 cm dan jari jari alasnya 20 cm, maka luas selimutnya adalah

s^2 = t^2 + r^2
= 48^2 + 20^2
= 2304 + 400
= akar kuadrat dari 2704 = 52 cm
luas selimut kerucut = phi r s
= 3,14 × 20 × 52
= 3.265,6 cm^2

Diket = t = 48 cm
             r = 20 cm
Dit = luas selimut
Jawab = garis pelukis = [tex] \sqrt{ t^{2} + r^{2} } [/tex]
                                          [tex] \sqrt{ 48^{2} + 20^{2} } [/tex]
                                          [tex] \sqrt{2304 + 400} [/tex]
                                          [tex] \sqrt{2704} [/tex]
                                          52 cm
                luas selimut = πrs
                                         3,14 x 20 cm x 52 cm
                                         3265,6 cm²